﻿@model bool?
@{
    string value=Model.HasValue?Model.Value.ToString():"";
    List<SelectListItem> list =new List<SelectListItem> { 
        new SelectListItem { Text = "", Value = "" }, 
        new SelectListItem { Text = "是", Value = "True" },
        new SelectListItem { Text = "否", Value = "False" }
    };
    list.ForEach(m => { if (m.Value == value) { m.Selected = true; } });
}
@Html.DropDownList("",list)